CN107707109B - A kind of power circuit and air conditioner - Google Patents
A kind of power circuit and air conditioner Download PDFInfo
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- CN107707109B CN107707109B CN201710980496.7A CN201710980496A CN107707109B CN 107707109 B CN107707109 B CN 107707109B CN 201710980496 A CN201710980496 A CN 201710980496A CN 107707109 B CN107707109 B CN 107707109B
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- 238000006243 chemical reaction Methods 0.000 claims abstract description 38
- 239000003990 capacitor Substances 0.000 claims description 66
- 230000001681 protective effect Effects 0.000 claims description 23
- 230000003071 parasitic effect Effects 0.000 claims description 22
- 230000001419 dependent effect Effects 0.000 claims description 10
- 101100328518 Caenorhabditis elegans cnt-1 gene Proteins 0.000 claims description 6
- 101000983292 Homo sapiens N-fatty-acyl-amino acid synthase/hydrolase PM20D1 Proteins 0.000 claims description 5
- 102100026873 N-fatty-acyl-amino acid synthase/hydrolase PM20D1 Human genes 0.000 claims description 5
- 238000001914 filtration Methods 0.000 claims description 3
- 230000000087 stabilizing effect Effects 0.000 claims 2
- 230000000740 bleeding effect Effects 0.000 description 11
- 238000010586 diagram Methods 0.000 description 6
- 238000007599 discharging Methods 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 230000002401 inhibitory effect Effects 0.000 description 2
- 230000007935 neutral effect Effects 0.000 description 2
- 238000006467 substitution reaction Methods 0.000 description 2
- 230000001052 transient effect Effects 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 1
Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/32—Means for protecting converters other than automatic disconnection
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/44—Circuits or arrangements for compensating for electromagnetic interference in converters or inverters
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
- H02M7/02—Conversion of ac power input into dc power output without possibility of reversal
- H02M7/04—Conversion of ac power input into dc power output without possibility of reversal by static converters
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- Electromagnetism (AREA)
- Emergency Protection Circuit Devices (AREA)
Abstract
A kind of power circuit and air conditioner, are related to electronic technology field, and the embodiment of the present application can prevent damage of the surge voltage to chip is controlled in power circuit.The power circuit includes: conversion circuit, control chip, transformer and vent unit；Conversion circuit connects AC power source, ac supply signal for exporting AC power source is converted to DC power signal, and the high-voltage signal of DC power signal is exported by the first DC output end, the low-voltage signal of DC power signal is exported by the second DC output end；The first end of transformer primary connects the first DC output end, the second end connection control chip of transformer primary；It controls chip and connects the second DC output end.The third end of the primary side of the input terminal and transformer of vent unit is connected, and the output end of vent unit connects protecting field.The application is applied to surge voltage of releasing in a power.
Description
Technical Field
The application relates to the technical field of electronics, especially, relate to a power supply circuit and air conditioner.
Background
The surge signal is a transient overvoltage or transient overcurrent caused by external lightning strikes, internal electrical equipment start/stop or faults. If the surge signal acts on the electrical equipment, the safety of the electrical equipment and users of the electrical equipment can be threatened, the reliability of the operation of the electrical equipment is also reduced, and protective measures need to be taken for the electrical equipment. In the prior art, a method of providing a discharge tube between a live wire and a ground wire at an ac power supply input end of a power supply circuit is generally adopted to discharge a surge.
In view of the above situation, the inventor of the present application has found that, when there is a surge on the zero line, the surge cannot be discharged by using the existing discharging method. When the surge voltage does not exceed the operating voltage of the discharge tube, the discharge tube does not function, and the surge voltage flows to the next stress portion. Therefore, when the surge is suppressed by adopting the prior art, the surge may be transmitted to the control chip through the distributed capacitance of each device on the circuit to the ground, so that the control chip is damaged.
Disclosure of Invention
The technical problem that the chip cannot be effectively protected by the existing surge discharging method is solved. The application provides a power supply circuit and air conditioner through the mode that sets up the unit of bleeding between the secondary side of transformer and protection ground to when making the surge appear in the power supply circuit, can make the surge bleed through this unit of bleeding, and avoided surge flow direction control chip, and then prevent surge voltage to control chip's damage.
In order to achieve the above purpose, the embodiment of the present application adopts the following technical solutions:
in a first aspect, an embodiment of the present application provides a power supply circuit, including: the device comprises a conversion circuit, a control chip and a transformer; the conversion circuit is connected with an alternating current power supply and used for converting an alternating current power supply signal output by the alternating current power supply into a direct current power supply signal, outputting a high-voltage signal of the direct current power supply signal through a first direct current output end and outputting a low-voltage signal of the direct current power supply signal through a second direct current output end; the first end of the primary side of the transformer is connected with the first direct current output end, and the second end of the primary side of the transformer is connected with the control chip; the control chip is connected with the second direct current output end;
the power supply circuit further includes: the input end of the bleeder unit is connected with the third end of the secondary side of the transformer, and the output end of the bleeder unit is connected with a protective ground; the bleeder unit has a first capacitance value C8, the first capacitance value C8 satisfying the following formula:wherein Cps1 is a parasitic capacitance value of the primary side of the transformer to the secondary side of the transformer, Cse is a parasitic capacitance value between the secondary side of the transformer and the protection ground, and Cps2 is a parasitic capacitance value between the control chip and the protection ground.
In the embodiment of the present application, when a surge occurs at the first dc output end of the conversion circuit, by providing the bleeding unit between the secondary side of the transformer and the protected ground, the capacitance value C8 of the bleeding unit satisfies:therefore, the surge can be discharged by the parasitic capacitance of the transformer primary side to the transformer secondary side and the capacitance of the transformer secondary side to the protective ground. Thereby avoid the surge through the primary side flow direction control chip of transformer and then damage control chip's problem.
In a second aspect, an embodiment of the present application provides an air conditioner, including the power circuit described in the first aspect. Based on the same inventive concept, the principles and advantages of the air conditioner can be found in the contents of the first aspect, and repeated descriptions are omitted.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below.
Fig. 1 is a power supply circuit according to an embodiment of the present disclosure;
fig. 2 is a schematic diagram of a power circuit and a surge voltage bleeding channel provided in an embodiment of the present application;
fig. 3 is a schematic diagram of a power circuit according to an embodiment of the present disclosure;
fig. 4 is a schematic structural diagram of a power supply circuit according to an embodiment of the present disclosure;
fig. 5 is a power supply circuit according to an embodiment of the present disclosure;
fig. 6 is a simplified structural diagram of a bleed channel when a surge voltage is present at a first output terminal of a conversion circuit according to an embodiment of the present application;
fig. 7 is a schematic diagram of a power supply circuit and a surge voltage relief channel when a surge voltage is present at a first output terminal of a conversion circuit according to an embodiment of the present application;
fig. 8 is a simplified structural diagram of a bleed channel when a surge voltage is present at a first output terminal of a converter circuit according to an embodiment of the present application.
Detailed Description
Embodiments of the present application are described below with reference to the accompanying drawings.
First, technical terms referred to in the present application are described as follows:
an X capacitance: an ampere-capacitor is used for suppressing power supply electromagnetic interference. The main roles in the circuit are: the cross-over connection is used for eliminating differential mode interference, EMI filtering, eliminating spark circuit and the like at two ends of a power input line, and the finished product of the electronic product is ensured to meet the EMC requirement.
Y capacitance: an ampere-capacitor is used for suppressing power supply electromagnetic interference. In applications, it is common to bridge the power supply output lines and the protection ground, respectively, for suppressing common mode interference, typically occurring in pairs (live-protected ground, neutral-protected ground).
The embodiment of the application is applied to a scene of surge leakage in a power supply circuit. Fig. 1 shows a power supply circuit to which an embodiment of the present invention is applied, which includes a conversion circuit 11, a control chip 12, and a transformer 13. Specifically, the conversion circuit comprises alternating current signal input ends AC1 and AC2 for connecting an alternating current power supply, and a grounding end E for connecting a protective ground. After receiving an alternating current power supply signal of an alternating current power supply, the conversion circuit converts the accessed alternating current power supply signal into a direct current power supply signal through filtering and rectification, and respectively outputs a direct current high-voltage signal through a first direct current output end VCC and a direct current low-voltage signal through a second direct current output end VDD. The input end 1 of the primary side of the transformer 13 is connected with the first direct current output end VCC of the conversion circuit 11, the input end 3 of the primary side of the transformer 13 is connected with the control chip 12, and the control chip 12 is connected with the second direct current output end VDD. Wherein the control chip 12 is used for controlling the current output of the conversion circuit 11 to the primary side of the transformer 13.
The conversion circuit 11 specifically includes: filter L1 and rectifier DM 1. The filter L1 is used to isolate the ac power supply from the power circuit and prevent EMC interference between the ac power supply and the power circuit, and a common mode inductor is usually used to implement the function of the filter L1. The rectifier DM1 is configured to rectify and convert the ac power signal output by the filter L1 into a dc power signal, and output a high-voltage signal of the dc power signal through the first dc output terminal VCC and output a low-voltage signal of the dc power signal through the second dc output terminal VDD. Specifically, a first input terminal 1 of the filter L1 is connected to the live line of the ac power source, and a second input terminal 2 of the filter L1 is connected to the neutral line of the ac power source, for example, the live line and the neutral line of 220V commercial power. A first input 1 of the rectifier DM1 is connected to a first output 3 of the filter L1, and a second input 2 of the rectifier DM1 is connected to a second output 4 of the filter L1; the rectifier DM1 rectifies the ac power signal output from the filter L1, and outputs the rectified dc power signal through the first dc output terminal and the second dc output terminal. The first output terminal 3 of the rectifier DM1 is connected to the resistor R1, the other end of the resistor R1 is connected to the first dc output terminal VCC of the converter circuit 11, and the first dc output terminal VCC is connected to the first input terminal 1 on the primary side of the transformer 13. The second output terminal 4 of the rectifier DM1 is connected to the second dc output terminal VDD of the conversion circuit 11 and connected to the control chip. The conversion circuit 11 further includes a capacitor C7, wherein one end of the capacitor C7 is connected to the first dc output terminal VCC, and the other end is connected to the second dc output terminal VDD.
Further, the conversion circuit 11 further includes a discharge tube DSA1, a varistor Z1, a varistor Z2, an X capacitor C1, and Y capacitors C3 and C4. One end of a discharge tube DSA1 is connected with a protective ground, and the other end is connected with an AC power live wire through a voltage dependent resistor Z2 and used for releasing surge voltage on a power grid. The voltage dependent resistor Z1 is connected between the live wire and the zero wire of the AC power supply and used for inhibiting the impulse voltage between the live wire and the zero wire. The X capacitor C1 is connected between the live wire and the zero wire of the alternating current power supply and used for releasing the differential mode interference signal between the live wire and the zero wire. The Y capacitor C3 is connected with the live wire and the protective earth wire, and the C4 is connected with the zero wire and the protective earth wire, and is used for releasing common-mode interference signals between the live wire and the zero wire. The conversion circuit further comprises an X capacitor C2, a Y capacitor C5 and C6. And the capacitor C2 is connected between the live wire output end and the zero wire output end of the filter and used for releasing the differential mode interference signal between the live wire and the zero wire. The Y capacitor C5 is connected between the live wire output end of the filter and the protective ground wire, and the C6 is connected between the zero line output end of the filter and the protective ground wire, and is used for releasing common-mode interference signals between the live wire and the zero line. Furthermore, a diode and a zener diode are connected in parallel between the first terminal 1 of the primary side of the transformer 13 and the second terminal 3 of the primary side of the transformer 13. Specifically, as shown in fig. 1, the first terminal 1 of the primary side of the transformer 13 is connected to the anode of the zener diode ZD1, the cathode of the zener diode ZD1 is connected to the cathode of the diode D1, and the anode of the diode D1 is connected to the second terminal 3 of the primary side of the transformer 13. The zener diode and the diode are used for absorbing the peak voltage caused by the leakage inductance of the transformer when the control chip turns off the power supply loop between the direct current output end of the conversion circuit 11 and the primary side of the transformer 13.
In the power supply circuit, when there is a surge voltage in the input ac power supply signal, as shown by eight thick dashed lines in fig. 2, there are the following 8 surge bleeding paths:
passage 1, vent passage of live wire to protection ground: piezoresistor Z2-discharge tube DSA 1-protective earth;
passage 2, vent passage of live wire to protection ground: y capacitance C3-protection ground;
channel 3, the discharge channel of the zero line to the protection ground: y capacitance C4-protection ground;
passage 4, vent passage of live wire to protection ground: filter L1-Y capacitor C6-protection ground;
passage 5, the discharge passage of the zero line to the protection ground: filter L1-Y capacitor C5-protection ground;
and after rectification, a first direct current output end is connected with a ground discharge channel of the channel 6: rectifier DM 1-transformer primary side to secondary side parasitic capacitance Cps 1-transformer secondary side to protective ground parasitic capacitance Cse-protective ground;
and after rectification, a second direct current output end is connected with a ground discharge channel of the channel 7: rectifier DM1-Y capacitance C9, C10-parasitic capacitance Cse of transformer secondary side to protection ground-protection ground;
and after rectification, a first direct current output end is connected with a ground discharge channel of the channel 8: rectifier DM 1-parasitic capacitance of control chip to protection ground Cps 2-protection ground.
It can be seen that in the above power supply circuit, when a surge voltage occurs in the circuit, the surge voltage is usually discharged through the ground terminal E of the conversion circuit 11, as in the channels 1 to 5. When the surge voltage is not discharged through the ground terminal E of the conversion circuit 11, the surge voltage flows to the next stress portion. At this time, the surge voltage may flow to the control chip 12 and the transformer 13 through the above-mentioned channels 6 to 8 via the output terminal of the conversion circuit 11.
When the surge voltage is discharged through the channel 8, the surge voltage flows into the control chip 12 through the first dc output terminal, the zener diode ZD1 and the diode D1, and then flows to the protection ground through the parasitic capacitor Cps2 between the control chip 12 and the protection ground, which may cause the control chip 12 to be damaged.
In view of the above technical problem, an embodiment of the present application provides a power circuit, as shown in fig. 3. The power supply circuit includes: a conversion circuit 11, a control chip 12 and a transformer 13. The conversion circuit 11 is connected to an ac power supply, and is configured to convert an ac power signal output by the ac power supply into a dc power signal, output a high-voltage signal of the dc power signal through a first dc output terminal VCC, and output a low-voltage signal of the dc power signal through a second dc output terminal VDD. The first end 1 of the primary side of the transformer 13 is connected with the first direct current output end VCC, and the second end 3 of the primary side of the transformer is connected with the control chip 12. The control chip 12 is connected to the second dc output terminal VDD.
The power supply circuit further includes: the input end of the bleeder unit 14 is connected with the third end of the secondary side of the transformer 13, and the output end of the bleeder unit 14 is connected with a protective ground; the bleeder unit has a first capacitance value C8, and the first capacitance value C8 satisfies the following formula:
wherein Cps1 is a parasitic capacitance value of the primary side of the transformer 13 to the secondary side of the transformer 13, Cse is a parasitic capacitance value between the secondary side of the transformer 13 and the protection ground, and Cps2 is a parasitic capacitance value between the control chip 12 and the protection ground.
Specifically, in the embodiment of the present application, as long as the surge can be discharged from the secondary side of the transformer 13, which pin of the secondary side of the transformer 13 the discharge unit 14 is connected to is not particularly limited. Specifically, as shown in fig. 2, the bleeding unit 14 may be connected to the pin 4 of the transformer, may be connected to the pin 5 of the transformer, or may be connected to the pin 6 of the transformer, as long as the surge can be bled from the secondary side of the transformer 13.
In one embodiment, as shown in fig. 3, the power supply circuit further includes a zener diode ZD1 and a diode D1. The first terminal 1 of the primary side of the transformer 13 is connected with the anode of the zener diode ZD1, the cathode of the zener diode ZD1 is connected with the cathode of the diode D1, and the anode of the diode D1 is connected with the second terminal 3 of the primary side of the transformer 13. The zener diode and the diode are used for absorbing the peak voltage caused by the leakage inductance of the transformer when the control chip turns off the power supply loop between the direct current output end of the conversion circuit 11 and the primary side of the transformer 13. In the prior art, when a surge voltage exists at the first dc output terminal VCC, the surge voltage may flow to the control chip through the zener diode ZD1 and the diode D1. And owing to be connected with the unit 14 that leaks between the pin of transformer secondary side and the protection ground in this application, and then when first direct current output VCC has surge voltage, can avoid surge voltage to flow to control chip through zener diode ZD1, diode D1 to can effectively protect control chip.
In one example, as shown in fig. 4, the conversion circuit 11 includes: filter L1, rectifier DM 1. The first input end of the filter L1 is connected with a live wire of an alternating current power supply, and the second input end of the filter L1 is connected with a zero wire of the alternating current power supply; a first input of the rectifier DM1 is connected to a first output of the filter, a second input of the rectifier DM1 is connected to a second output of the filter L1; the rectifier DM1 rectifies the ac power signal and outputs the rectified dc power signal through the first dc output terminal and the second dc output terminal.
Further, the conversion circuit further comprises a first piezoresistor unit ZU1, a first capacitor unit CU1, a second capacitor unit CU2, a third capacitor unit CU3, a fourth capacitor unit CU4, a fifth capacitor unit CU5 and a sixth capacitor unit CU 6; one end of the first voltage dependent resistor unit is connected with a live wire of an alternating current power supply, and the other end of the first voltage dependent resistor unit is connected with a zero line of the alternating current power supply; one end of the first capacitor unit CU1 is connected with a live wire of an alternating current power supply, and the other end of the first capacitor unit CU1 is connected with a zero wire of the alternating current power supply; one end of the second capacitor unit CU2 is connected to the first output end of the filter, and the other end is connected to the second output end of the filter; one end of the third capacitor unit CU3 is connected to the live wire of the ac power supply, and the other end is connected to the protection ground; one end of the fourth capacitor unit CU4 is connected with a zero line of an alternating current power supply, and the other end of the fourth capacitor unit CU4 is connected with a protection ground; one end of the fifth capacitor unit CU5 is connected to the first output end of the filter, and the other end is connected to the protection ground; one end of sixth capacitor unit CU6 is connected to the second output terminal of the filter, and the other end is connected to the protection ground.
In one embodiment, as shown in fig. 4, the conversion circuit 11 further includes: discharge tube DSA1, second varistor unit ZU 2. One end of the discharge tube DSA1 is connected with the protective ground, and the other end is connected with the live wire of the alternating current power supply through the second piezoresistor unit ZU2, and is used for releasing the surge voltage on the power grid. Since the surge voltage in the live line can be discharged through the following discharging unit 14 in the embodiment of the present application, the discharge tube DSA1 can also be omitted in the power supply circuit provided in the embodiment of the present application.
Each capacitor unit in CU1-CU7 may be formed by one or more capacitor devices connected in series and parallel. As shown in fig. 5, in one example, CU1 includes X capacitance C1, CU2 includes X capacitance C2, CU3 includes Y capacitance C3, CU4 includes Y capacitance C4, CU5 includes Y capacitance C5, and CU6 includes Y capacitance C6. ZU1 includes a piezo-resistor Z1. The voltage dependent resistor Z1 is connected between the live wire and the zero wire of the AC power supply and used for inhibiting the impulse voltage between the live wire and the zero wire. The X capacitor C1 is connected between the live wire and the zero wire of the alternating current power supply and used for releasing the differential mode interference signal between the live wire and the zero wire. The Y capacitor C3 is connected with the live wire and the protective earth wire, and the C4 is connected with the zero wire and the protective earth wire, and is used for releasing common-mode interference signals between the live wire and the zero wire. The conversion circuit further comprises an X capacitor C2, a Y capacitor C5 and C6. And the capacitor C2 is connected between the live wire output end and the zero wire output end of the filter and used for releasing the differential mode interference signal between the live wire and the zero wire. The Y capacitor C5 is connected between the live wire output end of the filter and the protective ground wire, and the C6 is connected between the zero line output end of the filter and the protective ground wire, and is used for releasing common-mode interference signals between the live wire and the zero line. Further, the second piezo-resistor ZU2 comprises a piezo-resistor Z2. Optionally, the conversion circuit 11 further includes a resistor R1 and a capacitor C7. One end of the resistor R1 is connected to the first output terminal of the rectifier DM1, the other end of the resistor R1 is connected to the first dc output terminal VCC of the converter circuit 11, and the first dc output terminal VCC is connected to the first input terminal 1 on the primary side of the transformer 13. A second output terminal of the rectifier DM1 is connected to the second dc output terminal VDD of the conversion circuit 11 and connected to the control chip. One end of the capacitor C7 is connected to the first dc output terminal VCC, and the other end is connected to the second dc output terminal VDD.
In the embodiment of the present application, it is considered that when there is a surge voltage at the first dc output VCC of the conversion circuit, the surge voltage may be discharged through two channels, "channel 6" and "channel 8" in fig. 2, and the structure of the simplified discharge channel is shown in fig. 6: in "channel 6", the surge voltage is discharged to the protective earth through a parasitic capacitance Cps1 between the primary side and the secondary side of the transformer and a parasitic capacitance Cse between the secondary side of the transformer and the protective earth. In "channel 8", the surge voltage is drained through the parasitic capacitance between the control chip and the protection ground, and further flows to the protection ground Cps 2. In order to avoid the surge voltage being discharged through the "channel 8" and damaging the control chip, the total capacitance in the "channel 6" needs to be increased so that the surge voltage is discharged through the "channel 6". Further, considering that the parasitic capacitance of the transformer is very difficult to control and adjust, as shown in fig. 3-5, the bleeding unit is connected between the secondary side of the transformer and the protection ground, that is, a bleeding unit is connected in parallel to the parasitic capacitance of the secondary side of the transformer to the protection ground, and the first capacitance value C8 of the bleeding unit satisfies the following formula:
and then when there is surge voltage at the first dc output VCC of the conversion circuit 11, the surge voltage can be discharged through the "channel 6" as much as possible, and the surge voltage is not discharged through the control chip, thereby effectively protecting the control chip. In a specific power circuit, as shown in fig. 7, when a surge voltage exists at the first dc output terminal and the surge voltage is discharged through the "channel 6" and the "channel 8", the structure of the simplified discharge channel is shown in fig. 6, in the present application, a Y capacitor C8 is connected between the secondary side of the transformer and the protection ground, so as to increase the capacitance between the secondary side of the transformer and the protection ground, and when the surge voltage exists at the first dc output terminal VCC of the conversion circuit 11, the surge voltage can be discharged through the "channel 6" as much as possible, and cannot be discharged through the "channel 8", i.e., through the control chip, so as to effectively protect the control chip.
In addition, since the power supply circuit provided in the embodiment of the present application prevents the control chip from being damaged by the surge voltage by adding one bleeder unit 14, a discharge tube connected to a live line in the converter circuit 11, that is, a discharge tube DSA1 in fig. 4, may be omitted in the power supply circuit provided in the embodiment of the present application. Therefore, the cost can be saved while the damage of the surge voltage to the control chip is effectively prevented.
Specifically, the first capacitance of the bleeder unit 14 ranges from 1000 to 2200 pF. The bleeding unit 14 may be a Y capacitor. In the present application, it is found that the capacitance values of Cps2, Cps1 and Cse are generally within 200pF by measuring the parasitic capacitance of the transformer and the control chip. Therefore, in order to increase the parasitic capacitance of the first channel, when the capacitance value of the bleeder unit is selected, the capacitance value is selected to be much larger than the parasitic capacitance of the transformer and the control chip, so that the capacitance value of 1000pF or more is selected. Meanwhile, experiments verify that in order to meet the requirement of safety-specified bleeder current, the capacitance value of the bleeder unit should be smaller than 2200 pF. Therefore, the first capacitance of the bleeder unit 14 in the present application ranges from 1000 to 2200 pF.
In one embodiment, the control chip is model number TNY278 PN. As shown in fig. 5, the drain D pin of the control chip is connected to the second end of the primary side of the transformer, the source S of the control chip is connected to the second dc output terminal, the enable pin EN is connected to the first dc output terminal VCC through a resistor R2, and the bypass pin BP is connected to the second dc output terminal VDD through a capacitor C11.
In one embodiment, as shown in fig. 4, the power circuit further includes a seventh capacitor unit CU7, wherein one end of the seventh capacitor unit is connected to the second dc output terminal, and the other end of the seventh capacitor unit is connected to the secondary side of the transformer. As shown in fig. 5, the seventh capacitive unit specifically includes Y capacitors C9 and C10, where C9 and C10 are connected in series. Specifically, as shown in a bleed-off channel "channel 7" in fig. 7, the seventh capacitance unit is configured to bleed off a surge voltage to the secondary side of the transformer when the surge voltage exists at the second dc output terminal, and then bleed off a parasitic capacitance of the secondary side of the transformer to the protection ground. Meanwhile, in the power circuit provided by the embodiment of the application, because the leakage unit is connected between the secondary side of the transformer and the protection ground, the total capacitance of the secondary side of the transformer to the protection ground is increased, and further the total capacitance of the channel 7 is increased, so that the leakage capacity of the channel 7 can be improved, and the surge current is prevented from flowing to the next stressed part.
In addition, this application embodiment still provides an air conditioner, and this air conditioner includes the above-mentioned power supply circuit that this application provided.
The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.
Claims (9)
1. A power supply circuit, comprising: the device comprises a conversion circuit, a control chip and a transformer;
the conversion circuit is connected with an alternating current power supply and used for converting an alternating current power supply signal output by the alternating current power supply into a direct current power supply signal, outputting a high-voltage signal of the direct current power supply signal through a first direct current output end and outputting a low-voltage signal of the direct current power supply signal through a second direct current output end; the first end of the primary side of the transformer is connected with the first direct current output end, and the second end of the primary side of the transformer is connected with the control chip; the control chip is connected with the second direct current output end;
the power supply circuit further includes: the input end of the bleeder unit is connected with the third end of the secondary side of the transformer, and the output end of the bleeder unit is connected with a protective ground; the bleeder unit has a first capacitance value C8, the first capacitance value C8 satisfying the following formula:wherein Cps1 is a parasitic capacitance value of the primary side of the transformer to the secondary side of the transformer, Cse is a parasitic capacitance value between the secondary side of the transformer and the protection ground, and Cps2 is a parasitic capacitance value between the control chip and the protection ground.
2. The power supply circuit according to claim 1,
the first capacitance value C8 is in the range of 1000-2200 pF.
3. The power supply circuit according to claim 1 or 2,
the conversion circuit includes: a filter, a rectifier; wherein,
the first input end of the filter is connected with the live wire of the alternating current power supply, and the second input end of the filter is connected with the zero line of the alternating current power supply;
the first input end of the rectifier is connected with the first output end of the filter, and the second input end of the rectifier is connected with the second output end of the filter; the first output end of the rectifier is connected with the first direct current output end, and the second output end of the rectifier is connected with the second direct current output end;
the filter is used for filtering an alternating current power supply signal input by the alternating current power supply;
the rectifier is used for rectifying the filtered alternating current power supply signal output by the filter to obtain the direct current power supply signal, outputting a high-voltage signal of the direct current power supply signal through the first direct current output end, and outputting a low-voltage signal of the direct current power supply signal through the second direct current output end.
4. The power supply circuit according to claim 3,
the conversion circuit further includes: the first voltage dependent resistor unit, the first capacitor unit, the second capacitor unit, the third capacitor unit, the fourth capacitor unit, the fifth capacitor unit and the sixth capacitor unit; one end of the first voltage dependent resistor unit is connected with a live wire of the alternating current power supply, and the other end of the first voltage dependent resistor unit is connected with a zero line of the alternating current power supply; one end of the first capacitor unit is connected with a live wire of the alternating current power supply, and the other end of the first capacitor unit is connected with a zero line of the alternating current power supply; one end of the second capacitor unit is connected with the first output end of the filter, and the other end of the second capacitor unit is connected with the second output end of the filter; one end of the third capacitor unit is connected with a live wire of the alternating current power supply, and the other end of the third capacitor unit is connected with the protective ground; one end of the fourth capacitor unit is connected with a zero line of the alternating current power supply, and the other end of the fourth capacitor unit is connected with the protection ground; one end of the fifth capacitor unit is connected with the first output end of the filter, and the other end of the fifth capacitor unit is connected with the protective ground; one end of the sixth capacitor unit is connected with the second output end of the filter, and the other end of the sixth capacitor unit is connected with the protective ground.
5. The power supply circuit according to claim 3,
the conversion circuit further includes: a second varistor unit and a discharge tube;
one end of the second voltage dependent resistor unit is connected with a live wire of the alternating current power supply, and the other end of the second voltage dependent resistor unit is connected with the discharge tube; the other end of the discharge tube is connected with a protective ground.
6. The power supply circuit according to claim 1 or 2, wherein the power supply circuit further comprises a diode, a zener diode;
the anode of the voltage stabilizing diode is connected with the first end of the primary side of the transformer, the cathode of the voltage stabilizing diode is connected with the cathode of the diode, the anode of the diode is connected with the control chip, and the anode of the diode is connected with the second end of the primary side of the transformer.
7. The power supply circuit according to claim 1 or 2,
the power supply circuit further comprises a seventh capacitance unit; one end of the seventh capacitor unit is connected to the second dc output terminal, and the other end of the seventh capacitor unit is connected to the fourth terminal of the secondary side of the transformer.
8. The power supply circuit according to claim 1 or 2,
the model of the control chip is TNY278 PN;
and a drain D pin of the control chip is connected with the second end of the primary side of the transformer, and a source S of the control chip is connected with the second direct current output end.
9. An air conditioner characterized by comprising the power supply circuit of any one of claims 1 to 8.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710980496.7A CN107707109B (en) | 2017-10-19 | 2017-10-19 | A kind of power circuit and air conditioner |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710980496.7A CN107707109B (en) | 2017-10-19 | 2017-10-19 | A kind of power circuit and air conditioner |
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| CN107707109A CN107707109A (en) | 2018-02-16 |
| CN107707109B true CN107707109B (en) | 2019-09-20 |
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| CN112978523B (en) * | 2021-04-02 | 2023-09-19 | 日立电梯（中国）有限公司 | Elevator control cabinet reliability ground equivalent verification system and method |
| CN116700106B (en) * | 2023-06-30 | 2024-04-19 | 合肥申威睿思信息科技有限公司 | Power-on and power-off time sequence control circuit and method |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JP2009232636A (en) * | 2008-03-25 | 2009-10-08 | Renesas Technology Corp | Charging device and semiconductor integrated circuit device |
| CN202058567U (en) * | 2011-05-05 | 2011-11-30 | 南海发展股份有限公司 | Lightning-proof isolation transformer |
| CN202172267U (en) * | 2011-08-23 | 2012-03-21 | 瑞斯康达科技发展股份有限公司 | An Ethernet interface protection circuit |
| CN202535063U (en) * | 2012-03-28 | 2012-11-14 | 冠捷显示科技(武汉)有限公司 | MOS tube grid electrode discharging circuit for main switch of switch power supply |
| CN204334331U (en) * | 2014-09-24 | 2015-05-13 | 帝发技术(无锡)有限公司 | The fans drive power supply of vehicle-mounted heater |
| US9750108B2 (en) * | 2015-04-02 | 2017-08-29 | Modern Home Lighting Inc. | Light emitting diode (LED) torchiere lamp with overheat and overvoltage protection functions |
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